Saturday, May 23, 2020

What's Dangerous, What Isn't

I have noticed that the Washington Post thinks any warming anywhere above 2°C, even just a bit above, is "dangerous":
Their analysis of global climate data showed the planet is heating up unevenly. Globally, average temperatures are a little more than 1 degree Celsius (1.8 degrees Fahrenheit) warmer than in the preindustrial era. But roughly one-tenth of the world’s surface area has already experienced 2 degrees Celsius of warming — an amount that U.N. scientists say will trigger dangerous climate impacts. In the United States, more than 70 counties have passed that threshold.
and not just here, but in prior articles too. Of course this is ridiculous not only in degree, but in kind. A warming of 2.06°C (say) isn't any more dangerous than 2.00°C, not really, given the uncertainties involved, which they don't seem to want to acknowledge. Uncertainties don't make the evening news.

But beyond that, "2.0°C" isn't any kind of magic line. It was chosen -- and I once asked several IPCC-ish scientists about this for something I was writing, many years ago -- out of convenience. 1°C seemed too small, and 3°C seemed too big. So 2°C it was. It was that simple, and, really, that simple.

But that hardly means 2°C anywhere is as dangerous as 2°C globally. WaPo is continually confused about this, too, from what I can tell over the years.

We can get a good approximation for land warming, WL, by noting a few simple, approximate relationships:


where A=area, W=warming, and G=global, O=ocean, L=land. (Am I good here?) For Mama Earth:

AO = 361.1 Mkm2
AL = 148.9 Mkm2
AG = 510.1 Mkm2

From NOAA:
WG = 1.05°C
WL = 1.62°C
WO = 0.85°C

which look more accurate than they really are, once you include uncertainties. So if WG = 2°C, WL = something like 3.1°C. And this is a global average; there's a lot of deviation by latitude. 

So just because some place on land exceeds 2°C of warming -- or 3.1°C -- doesn't mean it's suddenly dangerous-look-out-dive-for-the-shadows red flashing sirens. Please.


David in Cal said...

Nice post, David. People who are legitimately concerned about global warming can be undermined by exaggerations. E.g., a 20 year-old article in The Independent was since deleted, but skeptics keep alive this quote:

According to Dr. David Viner, a senior research scientist at the climatic research unit (CRU) of the University of East Anglia, within a few years snowfall will become “a very rare and exciting event”.

“Children just aren’t going to know what snow is,” he said

People can see that their lives are little changed so far. They will be turned off by a claim that there already has been a huge change.


Entropic man said...

I'm not sure that Donald Trump's walk has had quite the effect he wished.

David in Cal said...

Yes, Entropic man, this was a PR disaster for Trump. That's because the media apparently ran with a false story.

Statement from United States Park Police acting Chief Gregory T. Monahan about the actions taken over the weekend to protect life and property

Date: June 2, 2020

The United States Park Police (USPP) is committed to the peaceful expression of First Amendment rights. However, this past weekend’s demonstrations at Lafayette Park and across the National Mall included activities that were not part of a peaceful protest, which resulted in injuries to USPP officers in the line of duty, the destruction of public property and the defacing of memorials and monuments. During four days of demonstrations, 51 members of the USPP were injured; of those, 11 were transported to the hospital and released and three were admitted.

Multiple agencies assisted the USPP in responding to and quelling the acts of destruction and violence over the course of the weekend in order to protect citizens and property.

On Monday, June 1, the USPP worked with the United States Secret Service to have temporary fencing installed inside Lafayette Park. At approximately 6:33 pm, violent protestors on H Street NW began throwing projectiles including bricks, frozen water bottles and caustic liquids. The protestors also climbed onto a historic building at the north end of Lafayette Park that was destroyed by arson days prior. Intelligence had revealed calls for violence against the police, and officers found caches of glass bottles, baseball bats and metal poles hidden along the street.

To curtail the violence that was underway, the USPP, following established policy, issued three warnings over a loudspeaker to alert demonstrators on H Street to evacuate the area. Horse mounted patrol, Civil Disturbance Units and additional personnel were used to clear the area. As many of the protestors became more combative, continued to throw projectiles, and attempted to grab officers’ weapons, officers then employed the use of smoke canisters and pepper balls. No tear gas was used by USPP officers or other assisting law enforcement partners to close the area at Lafayette Park. Subsequently, the fence was installed.

Throughout the demonstrations, the USPP has not made any arrests. The USPP will always support peaceful assembly but cannot tolerate violence to citizens or officers or damage to our nation’s resources that we are entrusted to protect.